Astrophysics (Index)About

atmospheric window

(window)
(frequency bands within which the atmosphere passes EMR)

An atmospheric window is a band of frequencies (and wavelengths) over which the Earth's atmosphere allows electromagnetic radiation (EMR) to pass, given that the Earth's atmospheric transparency is limited. To other wavelengths, the atmosphere is opaque, which is a major motivation for space telescopes. Major atmospheric windows:

Within infrared and microwave, there are additional narrower windows, such as the water hole, which allows the 18-cm and 21-cm line to be viewed from the ground. The windows vary as to how transparent they are. Higher altitudes avoid some of the opaqueness, opening some windows to practical use and generally enhancing all the windows, the motivation for locating observatories at high altitudes. Water vapor in air also is a source of opaqueness for some microwave and infrared wavelengths, and dry air (such as found in deserts, and in very cold climates) also improves windows for astronomical use.

Atmospheric windows are a major factor in the behavior of the atmosphere, i.e., weather and climate, as they influence the Sun's warming effect and the Earth's cooling that balances it, i.e., the degree of the greenhouse effect. The windows' characteristics result from the atmosphere's constituents, its density, and how the constituents and density are distributed.


(EMR,optics,atmosphere,Earth,absorption)
Further reading:
https://en.wikipedia.org/wiki/Atmospheric_window
https://glossary.ametsoc.org/wiki/Atmospheric_window
https://scienceworld.wolfram.com/astronomy/AtmosphericWindows.html
https://gisgeography.com/atmospheric-window/
https://www.gb.nrao.edu/GBTopsdocs/primer/atmospheric__windows_.htm
http://spiff.rit.edu/classes/ast613/lectures/windows/windows.html

Referenced by pages:
1.3-mm observation
Atacama Desert
atmosphere
Balmer series (H)
bolometer
Brackett series
carbon (C)
continuous absorption
EMPIRE Survey
equilibrium temperature (Teq)
extinction
Gattini-IR
greenhouse effect
H-alpha (Ha)
H-beta (Hβ)
helium 1083 nm line
Humphreys series
hydrogen cyanide (HCN)
hydroxyl (OH)
infrared (IR)
ionized carbon fine structure line ([CII])
ionosphere
K band
Large Millimeter Telescope (LMT)
line blanketing
Llano de Chajnantor Observatory
low frequency radio astronomy
Lyman break (LB)
Lyman continuum (LyC)
Lyman-alpha blob
microwave
mid infrared (MIR)
MKO photometric system
MORA
near infrared (NIR)
Paschen series
passband
Pfund series
plasma frequency
precipitable water vapor (PWV)
radiative transfer (RT)
radio astronomy
S-Star Cluster
SCAP
Strömgren photometric system
survey depth
telescope
ultraviolet (UV)
ultraviolet astronomy
vegetation red edge (VRE)
Very Small Array (VSA)
visible light
water (H2O)

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